Browsing by Subject "Agrilus planipennis"

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    Associational protection and potential non-target effects of systemic insecticide treatments against emerald ash borer
    (2022-03) Mwangola, Dorah
    Emerald ash borer (EAB), Agrilus planipennis, is an invasive beetle that was accidentally introduced to North America from Asia. In North America, EAB attacks and kills ash trees (Fraxinus spp.). Since the 1990s the insect has spread to 35 American states and 5 Canadian provinces. A primary management strategy against EAB in urban centers is the use of systemic insecticide treatments. However, insecticide application can be very costly and induces concern about potential non-target effects on other invertebrate species and the environment. The objectives of this dissertation were to investigate the use of a treatment regime that could reduce costs, amounts of insecticides, and potential indirect negative effects on ash trees and other invertebrates. We hypothesized that treating a subset of ash trees in an urban setting could confer protective benefits to untreated trees, a strategy known as associational protection. We set up a study from summers 2017 to 2021 where 50% of boulevard ash trees at twelve sites distributed across eight cities in central and southeastern Minnesota were treated in a spatial gradient with one of two insecticides: emamectin benzoate (TREE-äge® G4) or azadirachtin (AzaSol®). Each site covered an area of approximately 1 km2 and contained approximately 100 ash trees. In general, treating a subset of trees increased the overall crown health of the study trees. We also conducted field and laboratory studies to analyze the indirect effect of insecticides on ash tree phenology and seed resources as well as non-target effects on other insect species. No adverse effects of chemical treatments were observed on ash tree phenology or seed germination or viability or time to germination. Non-target insect studies showed that there will likely be minimal effects on other invertebrates. Results from this study will assist in amending current treatment regimens using systemic insecticides and elucidate potential risks these insecticides may have on non-target invertebrates and ash trees.
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    The effects of feeding and overwintering conditions on emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) energy reserves and flight performance
    (2017-07) Tussey, Dylan
    The emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) is an invasive beetle from Asia that has been confirmed in 30 states as of July 2017. The spread of A. planipennis has been markedly slower in Minnesota than in other states. Cold winter temperatures are thought to be the primary factor for the slower spread. The goals of this study were to determine the role of adult feeding on A. planipennis energy reserves and flight capacity, as well as to elucidate any sub-lethal effects of winter conditions on A. planipennis flight capacity. In 2015 and 2016, adult A. planipennis were reared from infested green ash logs collected in Hennepin and Ramsey Counties, MN. A separate experiment was conducted by collecting infested logs from St Paul, MN and stored in two locations during the winter of 2015-2016. Grand Rapids, MN, and St Paul, MN, to determine how winter conditions affect A. planipennis energy reserves and flight capacity. Adults were individually placed in cages and provided with fresh, lab-grown shamel ash (Fraxinus uhdei Wenzig) leaves on which to feed for 0-20 days before being flash frozen or flown on a custom flight mill for 24 hours under constant light. Beetles were subjected to nutrient analysis using either petroleum ether or colorimetric assays. Feeding treatments were compared for weight and lipid gain, flight velocity and total distance flown.
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    Flight capacity of emerald ash borer Agrilus planipennis (Coleoptera: Buprestidae) and its parasitoid Tetrastichus planipennisi (Hymenoptera: Eulophidae), in response to several experimental treatments
    (2014-12) Fahrner, Samuel Joseph
    Emerald ash borer Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) is an invasive beetle native to eastern Asia. Tetrastichus planipennisi Yang (Hymenoptera: Eulophidae) is one of three hymenopteran parasitoids currently being introduced into North America as part of a classical biological control program against emerald ash borer. Here, custom-built, computer-monitored flight mills were used to measure the effects of age, feeding status, mating status, sex, and size on flight metrics of T. planipennisi. The flight mill was then used to measure flight metrics of emerald ash borer and T. planipennisi across a range of temperatures and relative humidity. The relationship between flight energetics, specifically flight distance, with temperature was then integrated with landscape temperatures at ten locations throughout the continental United States to compare relative dispersal capacity for emerald ash borer and T. planipennisi. The goal of this research was to elucidate factors that mediate the flight capacity of both insects and, for T. planipennisi, to infer the pre- and post-release conditions that may optimize flight capacity.